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arXiv 2104.02893physics.plasm-ph
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微波和Laser瑞利散射联合诊断针-针纳秒放电

Combined Microwave and Laser Rayleigh Scattering Diagnostics for Pin-to-Pin Nanosecond Discharges

Xingxing Wang, Adam Patel, Alexey Shashurin

摘要:

在这项工作中,通过微波瑞利散射(MRS)和激光瑞利散射(LRS)的组合测量的时间衰减的电子产生的大气针到针纳秒放电工作在火花制度。由于纳秒脉冲的初始能量沉积,在电子衰变的时间尺度上发生局部气体密度的变化。因此,当从MRS测量中提取电子数数据时,恒定碰撞频率的假设不再适用。为了重新校准整个电子衰变期间的MRS测量,在事件持续时间内进行局部气体密度的时间分辨LRS测量。局部气体密度被测得为30%的环境水平,在电子衰变的后期阶段,并恢复在约1毫秒后的放电。另外还观察到一个速度约为500 m/s的冲击波阵面。结合通过时间分辨ICCD成像进行的等离子体体积校准,给出了电子数和电子数密度的校正衰减曲线,测得的峰值电子数密度为4.5*10^15 cm^-3,衰减速率约为0.1-0.35*10^7 s^-1。混合MRS和LRS诊断技术可以应用于大气压微等离子体中的数气体密度的变化,预计由于在放电中的能量沉积的广谱。

英文摘要:

In this work, the temporal decay of electrons produced by an atmospheric pin-to-pin nanosecond discharge operating in the spark regime was measured via a combination of microwave Rayleigh scattering (MRS) and laser Rayleigh scattering (LRS). Due to the initial energy deposition of the nanosecond pulse, a variance in local gas density occurs on the timescale of electron decay. Thus, the assumption of a constant collisional frequency is no longer applicable when electron number data is extracted from the MRS measurements. To recalibrate the MRS measurements throughout the electron decay period, temporally-resolved LRS measurements of the local gas density were performed over the event duration. Local gas density was measured to be 30% of the ambient level during the later stages of electron decay and recovers at about 1 ms after the discharge. A shock front traveling approximately 500 m/s was additionally observed. Coupled with plasma volume calibration via temporally-resolved ICCD imaging, the corrected decay curves of the electron number and electron number density are presented with a measured peak electron number density of 4.5*10^15 cm^-3 and decay rate of ~ 0.1-0.35*10^7 s^-1. A hybrid MRS and LRS diagnostic technique can be applied for a broad spectrum of atmospheric-pressure microplasmas where a variation in number gas density is expected due to an energy deposition in the discharge.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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